Time-Optimal Path Tracking for Dual-Arm Free-Floating Space Manipulator System Using Convex Programming

Abstract

In this paper, the time-optimal path tracking problem of the dual-arm free-floating space manipulator (FFSM) system is solved by using convex programming. Firstly, we construct a continuous nonlinear optimization problem that considers system dynamics and constraints along the path, including torque, velocity and acceleration. Subsequently, the original optimization problem is transformed into a convex optimal control problem by using scalar path coordinate and nonlinear variables. To characterize the problem in a more manageable form, we apply the direct transcription method and discretize the problem into a sparse convex optimization program. Numerical results demonstrate that the proposed approach efficiently determines the trajectory of the FFSM along the preset path. Meanwhile, the base's velocity can be limited to a small region, which is an essential requirement for ensuring the stability of the satellite. Furthermore, an experiment is conducted using GLUON robots. The tracking error between the actual and preset pose of the target verifies the feasibility of the proposed method.